type Weekday = 'Monday' | 'Tuesday' | 'Wednesday' | 'Thursday' | 'Friday';
type Schedule = Record<Weekday, string>;

function createEmptySchedule(): Schedule {
    return {
        Monday: '',
        Tuesday: '',
        Wednesday: '',
        Thursday: '',
        Friday: '',
    };
}

const schedule: Schedule = createEmptySchedule();
schedule.Monday = 'Math';
schedule.Tuesday = 'History';
schedule.Wednesday = 'Science';
schedule.Thursday = 'English';
schedule.Friday = 'Gym';

console.log(schedule);
/**
{
  Monday: 'Math',
  Tuesday: 'History',
  Wednesday: 'Science',
  Thursday: 'English',
  Friday: 'Gym'
}
*/